Summer has arrived, and while it brings longer days and the promise of warm, sunny weather, it also brings flies and other biting insects that can make life a misery for horse and rider alike. In this guide, we outline the main types of fly that can cause irritation or harm to your horse, as well as how you can protect your horse this summer.
Flies can cause great irritation and distress to horses. Sweet itch can be notoriously irritating and difficult to manage, and this can affect the horse’s wellbeing and behaviour in the stable, during turnout, and when being ridden or lunged. Some flies can also transmit diseases — in the UK, eye infections can spread through a herd via flies.
There are 5 different types of fly that can will concern horse owners, and they can each affect horses in different ways:
Biting midges are responsible for the allergic skin reaction known as sweet itch. Sweet itch can be incredibly frustrating for both horse and owner, and sweet itch symptoms include excessive itching, patchy hair loss, agitation and irritability. You can find out more about how to treat and manage sweet itch in our guide for horse owners.
Similar to culicoides, black flies are small biting flies that usually target the horse’s head area, especially around the ears. Black fly bites can also be responsible for sweet itch in horses.
Horse flies are mainly found in woodlands and shaded areas. Horse fly bites usually cause a large local reaction in the skin, and they often target horse riders as well.
House flies like to feed on mucous secretions, especially around the eyes, and they can cause conjunctivitis in horses.
There are three main species of bot fly that affect horses in the UK, and they are differentiated by where they lay their eggs on the horse:
Bot flies are very large flies, and they carry a bundle of eggs. When horses groom themselves or others, the eggs can be transferred into the mouth where they burrow into the tissues as larvae and find their way to the stomach.
Eventually, the larvae mature and exit the horse’s body in the faeces. The larvae then pupate in the soil, before emerging as adult botflies.
Left untreated, a severe bot fly infestation can lead to ulceration, impaction colic, peritonitis and other life-threatening conditions. However, this is rare.
So, now that you know the main types of fly to look out for, here’s how you can protect your horse against them.
Flies are an ever-present problem during the summer months, but there are things you can do to minimise their impact on your horse. Below are five main things you can do to protect your horse from flies this summer.
Flies tend to gather in large numbers, often in places like stable yards. Manure, horses, and stagnant water can all attract flies to your yard, but there are things you can do to deter them.
Cover the muck heap with a black plastic sheet, to reduce the smell and help make it less attractive to flies. Ensure that any ditches are drained, so that water isn’t allowed to sit for long periods of time. Furthermore, do not allow water to gather in old dirty buckets, bins, or wheelbarrows that have been left around the yard.
Keeping your horse’s turnout clean with regular “poo picking” is also important to reducing the number and proximity of flies.
Culicoides midges are most prevalent at dawn and at dusk. So, if possible, keep your horse in their stable at these times. The horse fly is most present in wooded, shady areas, so avoid hacking through any woods, especially on warm days.
Flies are attracted to warm, sweaty horses (and humans), so it’s a good idea to ride during the cooler parts of the day when the horse is less likely to sweat. You may also want to make use of an indoor arena, if you have one.
Washing your horse after exercise will help remove the sweat that flies are attracted to. There are several horse shampoos available on the market containing natural or synthetic fly repellents, which can also help.
Check your horse for bot fly eggs daily. Use hot water and a sponge to loosen the sticky bot eggs, then scrape them off with a bot knife. Applying a thin layer of baby oil to your horse’s coat can help prevent bot fly eggs from sticking to the hair.
Fly rugs and fly masks can be highly effective in physically preventing flies and other biting insects from getting to your horse’s skin.
There is a wide range of sprays, creams, gels and wipes on the market containing a variety of active ingredients, from natural solutions like citronella, to powerful synthetic substances such as DEET.
Some of the most popular natural remedies are extracts of lavender, rosemary, tea tree and eucalyptus. Adding garlic to a horse's diet has also been recommended as a way of deterring flies.
Remember, fly repellents will only be effective for a limited time. Reapplication during the day is advised to keep levels high, especially if it rains, since repellents are not waterproof.
Important: Some fly repellents are competition-safe, but others aren’t. Always check the ingredients and your governing body’s rulebook before using fly repellent if you plan to compete.
Flies aren’t just an annoyance for horses — they can cause significant discomfort, stress, and even health issues. Fortunately, there are several steps you can take to minimise their presence and the irritation they cause to you and your horse.
By keeping your horse, yard, and turnout clean, using repellents and considering when and where you ride, you can help your horse stay comfortable this summer.
If you need advice on protecting your horse or pony from flies, or you suspect your horse is suffering from sweet itch, conjunctivitis, or a bot fly infestation, be sure to contact your equine vet. At Avonvale, we are always happy to support and advise our clients on preventing, managing, and repelling flies, and our experienced and trusted equine vet team are always on-hand to help.
The best fly repellent for your horse will depend on the type and severity of the flies, how easy the repellent is to apply and use, and whether you require a competition-safe fly repellent. Some fly repellents come as sprays, which are easy to apply quickly and frequently. Others come as shampoos, which are great for a post-ride wash. Some equine fly repellents are available as tags, which you can attach to your horse’s rug, tack, or even a mane or tail plait.
Most equine fly sprays are effective for around 6-12 hours, but this will vary by product. Heavy sweating, bathing, and rain will wash the spray off, so it is important to reapply the fly spray if your horse gets wet and after exercise. Most horse owners will apply fly spray in the morning and evening, as well as after bathing and exercise.
Start applying fly repellent as soon as the weather begins to warm up, before your horse starts itching. Once the horse has been bitten and starts to react, they will enter a cycle of rubbing and scratching the affected area, often making it worse in the process. Speak to your vet, as they will be able to advise you on how to minimise and manage sweet itch.
At Avonvale Equine Vet Practice, we are proud to offer a fully ambulatory equine veterinary service, delivering expert care at your yard across Warwickshire, Oxfordshire, Northamptonshire, Gloucestershire, and Worcestershire. Whether you need routine equine veterinary services such as vaccinations and worm egg counts, or advanced diagnostic investigations and treatments, our specialist equine veterinary team is here to support you and your horse.
We work with a wide range of clients — from leisure riders to competitive amateurs and professional yards — providing high-level equine veterinary care tailored to your specific needs. Our experienced and highly qualified equine vets offer specialist services including performance horse medicine, and advice for owners and riders at all levels. We are always on-hand to support you when it comes to your horse’s health and wellbeing.
With Avonvale Equine Vet Practice, you can rest assured that your horse’s care is in expert hands. Our dedicated team of equine vets is on-call 24 hours a day, 7 days a week, ensuring you always see one of our own vets, day or night.
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